全文获取类型
收费全文 | 806717篇 |
免费 | 54914篇 |
国内免费 | 2157篇 |
专业分类
耳鼻咽喉 | 10282篇 |
儿科学 | 26182篇 |
妇产科学 | 20272篇 |
基础医学 | 123600篇 |
口腔科学 | 22359篇 |
临床医学 | 71994篇 |
内科学 | 156746篇 |
皮肤病学 | 18196篇 |
神经病学 | 58932篇 |
特种医学 | 29761篇 |
外国民族医学 | 98篇 |
外科学 | 118801篇 |
综合类 | 16435篇 |
现状与发展 | 2篇 |
一般理论 | 206篇 |
预防医学 | 56869篇 |
眼科学 | 17984篇 |
药学 | 61951篇 |
5篇 | |
中国医学 | 2855篇 |
肿瘤学 | 50258篇 |
出版年
2021年 | 7533篇 |
2019年 | 7290篇 |
2018年 | 10143篇 |
2017年 | 7842篇 |
2016年 | 8691篇 |
2015年 | 9731篇 |
2014年 | 13150篇 |
2013年 | 19451篇 |
2012年 | 26094篇 |
2011年 | 27244篇 |
2010年 | 16346篇 |
2009年 | 15153篇 |
2008年 | 24927篇 |
2007年 | 26658篇 |
2006年 | 26814篇 |
2005年 | 25121篇 |
2004年 | 24966篇 |
2003年 | 23649篇 |
2002年 | 23126篇 |
2001年 | 39731篇 |
2000年 | 40242篇 |
1999年 | 33146篇 |
1998年 | 9047篇 |
1997年 | 7559篇 |
1996年 | 7807篇 |
1995年 | 7429篇 |
1994年 | 6781篇 |
1993年 | 6260篇 |
1992年 | 24623篇 |
1991年 | 24562篇 |
1990年 | 23695篇 |
1989年 | 23414篇 |
1988年 | 21260篇 |
1987年 | 20514篇 |
1986年 | 19552篇 |
1985年 | 18269篇 |
1984年 | 13422篇 |
1983年 | 11413篇 |
1982年 | 6369篇 |
1979年 | 12056篇 |
1978年 | 8509篇 |
1977年 | 7173篇 |
1976年 | 6914篇 |
1975年 | 7671篇 |
1974年 | 8947篇 |
1973年 | 8573篇 |
1972年 | 8058篇 |
1971年 | 7492篇 |
1970年 | 7211篇 |
1969年 | 6648篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
61.
T Oda N Yoshizawa S Oshima A Takeuchi T Kubota S Kondo Y Oshikawa Y Akashi Y Suzuki H Niwa 《Nihon Jinzo Gakkai shi》1990,32(6):631-641
To investigate the role of cell-mediated immunity (CMI) in glomerulonephritis (GN), we identified the infiltrating immune cells both within the glomerulus and in the interstitium. Frozen sections from 103 patients with various forms of GN: 10 with minor glomerular abnormality (MGA) as control, 10 with minimal change nephrotic syndrome (MCNS), 10 with membranous nephropathy (MN), 9 with focal glomerulosclerosis (FGS), 30 with IgA nephropathy (IgAN), 22 with acute post streptococcal glomerulonephritis (APSGN), and 2 with rapidly progressive glomerulonephritis (RPGN) were examined using monoclonal antibodies (MoAb) by indirect immunoalkaline-phosphatase labelling. In most glomerulonephritis, monocyte/M phi and helper/inducer T cells were predominantly infiltrating in the interstitium, but intraglomerular infiltration was rare, except for APSGN. This interstitial infiltration increased proportionally to the level of serum creatinine, and was most prominent in RPGN. Apparently different distribution was seen in APSGN, that is, prominent increase in total number of intra-glomerular monocyte/M phi infiltration with slightly increased T cells. The change was correlated with time after onset; namely the more leucocytic infiltration was observed when the tissue was taken earlier. These data suggest that in APSGN, monocyte/M phi accumulate in glomeruli via cell mediated immunity in addition to humoral immune mechanism resulting in glomerular hypercellularity, whereas in most chronic glomerulonephritis interstitial leucocyte infiltration, particularly helper T cells and monocyte/M phi may play an important role in the progression of glomerulonephritis. 相似文献
62.
In experiments on albino rats it was established that three administrations of indomethacin in a dose of 0.01 g/kg body weight induced a severe damage of the liver characterized by disturbances of hepatocytic membranes, bile-producing and protein-producing functions of the liver, an enhancement of lipid peroxidation, a decrease of reduced glutathione pool. Antioxidants (tocopherol acetate, essentiale, legalon, flacumin) limit manifestations of indomethacin, hepatotoxicity, as a result of which tha functional-biochemical disorders in the liver show up to a lesser degree. During the combined use of antioxidants in indomethacin-induced lesions of the liver their hepatoprotective activity increases. 相似文献
63.
64.
A Espinosa de los Monteros G Roussel N M Neskovic J L Nussbaum 《Journal of neuroscience research》1988,19(2):202-211
A new chemically defined medium consisting of equal parts of Dulbecco modified Eagle's and Ham's F-12 media supplemented with insulin, sodium selenite, putrescine, and D+ galactose, which allows the long-term survival of mature oligodendrocyte pure cultures, is described. Immunohistochemical staining has shown that over 90% of the cells become positive for myelin proteins shortly following subculture. Contaminating astrocytes (2%) do not survive in this medium. Biochemical data have indicated that these purified oligodendrocytes express 2'3'-cyclic nucleotide 3'-phosphohydrolase and UDP-galactose ceramide galactosyltransferase activities. Electron microscopical examination revealed that the oligodendrocytes were mostly of medium-dark type and appeared to be identical to cells cultured in serum-containing medium. The ability to maintain pure oligodendrocyte cultures in such a defined medium will allow investigations concerning exogenous and endogenous factors involved in oligodendrocyte metabolism. 相似文献
65.
Reduction of reticulata neuronal activity by zolpidem and alpidem, two imidazopyridines with high affinity for type I benzodiazepine receptors 总被引:1,自引:0,他引:1
G Mereu G Carcangiu A Concas N Passino G Biggio 《European journal of pharmacology》1990,179(3):339-345
Zolpidem and alpidem, two imidazopyridines with high affinity for the type I benzodiazepine recognition site, have recently been proposed as preferential hypnotic (zolpidem) and anxiolytic (alpidem) drugs notable for the minor incidence of side-effects. To further characterize the molecular mechanism involved in the action of these drugs, we studied their effects in comparison with those of diazepam on the spontaneous electrical activity of substantia nigra pars reticulata (SNR) neurons. These cells have been shown to be extremely sensitive to various positive and negative modulators of GABAergic transmission. All three drugs consistently produced a dose-dependent (0.03-8.0 mg/kg i.v.) inhibition of the firing of SNR cells when administered as a single bolus. However, zolpidem was more potent and efficacious than diazepam or alpidem. The ID50s were 0.076, 0.492 and 0.821 mg/kg, respectively. When the drugs were injected in exponentially (ratio 2) increasing doses up to 8.0 mg/kg, the rank order for tachyphylaxis was zolpidem much greater than diazepam greater than alpidem. Since the effects of the drugs were abolished and prevented by a small dose (0.5 mg/kg i.v.) of flumazenil (Ro 15-1788), it is likely that the effects were mediated through activation of benzodiazepine receptors. The results indicate that the hypnotic, zolpidem, has a more potent inhibitory action on SNR cell activity than the anxiolytics, alpidem and diazepam. 相似文献
66.
H Murakami M Togawa S Takahashi N Kasahara J Yamamoto N Matsuura Y Koshiyama Y Ino M Oda 《Arzneimittel-Forschung》1990,40(12):1352-1358
The effects of FUT-187 (6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate, CAS 103926-82-5), a novel synthetic protease inhibitor, were examined in experimental rat and canine models of pancreatitis. 1. FUT-187 significantly increased the survival of rats with trypsin- and phospholipase A2-induced pancreatitis in a dose-dependent manner (10-100 mg/kg, p.o.). 2. FUT-187 decreased plasma enzymatic activity reflecting the degree of pancreatitis in rats with ethionine-induced pancreatitis, and showed a tendency to ameliorate histopathological changes in the pancreas (10-100 mg/kg p.o.). 3. FUT-187 (10 mg/kg) produced an obvious improvement of various biochemical parameters of pancreatitis and also reduced histopathological changes in the pancreas in animals with experimental pancreatitis produced by the closed duodenal loop method. In addition, FUT-187 significantly increased the survival of dogs when given by direct administration into the lumen of the closed duodenal loop. The therapeutic effects of FUT-187 in experimental pancreatitis were nearly equal in most instances to those of camostat mesilate. Thus, FUT-187 would appear to be an effective new agent for the treatment of pancreatitis. 相似文献
67.
Multicentricity of hepatocellular carcinoma (HCC) is considered, especially in patients with liver cirrhosis. This paper describes an operative case of a male patient with probable multicentric development of HCC in precirrhotic fibrosis. The main tumors inside the capsule were completely necrotic due to transarterial embolization (TAE). Histologic examination disclosed discrete tiny nodules of HCC that were not detected grossly. They showed highly differentiated trabecular arrangements: Edmondson I. A scirrhous type was noted in the center of the tumors. At the borders of the tumors the carcinoma cells exhibited replacing growth patterns and it was thought that they developed multicentrically. Partial resection must be performed as extensively as possible in a case such as the present one. 相似文献
68.
69.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy. 相似文献
70.